Chapter 5 Appendicular Skeleton 126 bones Shoulder Girdle

Chapter 5 Appendicular Skeleton (126 bones)

Shoulder Girdle – aka Pectoral Girdle • 2 bones – Clavicle – collarbone • Attaches to manubrium and scapula • Helps form shoulder joint – holds shoulder away from thorax – Scapula – shoulder blades • Acromion – joins clavicle at acromioclavicular joint • Coracoid process – anchors muscles • Glenoid cavity – socket for humerus

• Only directly connected to axial skeleton at sternoclavicular joint • Allow for easy scapula movement – but is easily dislocated

Upper Limb • Arm – humerus – Head – joins scapula at glenoid cavity – Greater/lesser tubercles – muscle attachment – Deltoid tuberosity – ½ way down – deltoid attachment – Trochlea and capitulum – join forearm – Coronoid and olecranon fossas – allow elbow movement

• Forearm – Radius • Lateral – on thumb side with palm out • Head joins capitulum • Radial tuberosity – bicep attachment – Ulna • Medial – on little finger side with palm out • Coronoid and olecranon processes surround trochlea – Connected by interosseous membrane – Styloid process on distal end of both

• Hand – Carpals – carpus (wrist) – 2 irregular rows of 4 bones each – Metacarpals – palm - #1 -5 from thumb – Phalanges – fingers – 14 bones • 3 in fingers, 2 in thumbs

Pelvic Girdle • 2 coxal bones – aka ossa coxae – hip bones • When combined with sacrum and coccyx = pelvis • Attach securely to axial skeleton • Bear weight of upper body • Protect reproductive organs, bladder, large intestines

• Formed from 3 fused bones – Ilium • Connects to sacrum at sacroiliac joint • Upper edge – iliac crest – Ischium • Inferior (bottom) portion • Ischial tuberosity – receives weight when sitting – Pubis – pubic bone • Pubic symphysis – cartilaginous anterior joint btw the pubic bones – forms pubic arch • All 3 fuse at acetabulum – socket for femur

• 2 regions – False pelvis – medial to flaring portions of ilia – True pelvis – inferior to ilia – surrounded by bone • Male and female slightly differ • Female is adapted for childbirth

Lower Limbs • Thigh – femur – Greater/lesser trochanters – muscle attachment – Joins hips at acetabulum – held tightly – Lateral and medial condyles – join tibia • Separated by intercondylar fossa – Patellar surface – joint w/ patella

• Leg – Tibia – shinbone – medial • Medial and lateral condyles join femur – Separated by intercondylar eminence • Tibial tuberosity – patellar ligament joins • Medial malleolus – inner bulge of ankle – Fibula – very thin • Lateral malleolus – outer bulge of ankle

• Foot – Tarsals – tarsus – 7 bones • Posterior ½ of foot • Weight carried by 2 largest – Calcaneus – heelbone – Talus – btw tibia and calcaneus – Metatarsals – sole – 5 bones – Phalanges – toes – 14 bones • Toes have 3 each, big toe has 2